<?php
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2017, British Columbia Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @package	CodeIgniter
 * @author	EllisLab Dev Team
 * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
 * @copyright	Copyright (c) 2014 - 2017, British Columbia Institute of Technology (http://bcit.ca/)
 * @license	http://opensource.org/licenses/MIT	MIT License
 * @link	https://codeigniter.com
 * @since	Version 1.0.0
 * @filesource
 */
defined('BASEPATH') or exit('No direct script access allowed');

/**
 * CodeIgniter Calendar Class
 *
 * This class enables the creation of calendars
 *
 * @package CodeIgniter
 * @subpackage Libraries
 * @category Libraries
 * @author EllisLab Dev Team
 * @link https://codeigniter.com/user_guide/libraries/calendar.html
 */
class CI_Calendar
{

    /**
     * Calendar layout template
     *
     * @var mixed
     */
    public $template = '';

    /**
     * Replacements array for template
     *
     * @var array
     */
    public $replacements = array();

    /**
     * Day of the week to start the calendar on
     *
     * @var string
     */
    public $start_day = 'sunday';

    /**
     * How to display months
     *
     * @var string
     */
    public $month_type = 'long';

    /**
     * How to display names of days
     *
     * @var string
     */
    public $day_type = 'abr';

    /**
     * Whether to show next/prev month links
     *
     * @var bool
     */
    public $show_next_prev = FALSE;

    /**
     * Url base to use for next/prev month links
     *
     * @var bool
     */
    public $next_prev_url = '';

    /**
     * Show days of other months
     *
     * @var bool
     */
    public $show_other_days = FALSE;
    
    // --------------------------------------------------------------------
    
    /**
     * CI Singleton
     *
     * @var object
     */
    protected $CI;
    
    // --------------------------------------------------------------------
    
    /**
     * Class constructor
     *
     * Loads the calendar language file and sets the default time reference.
     *
     * @uses CI_Lang::$is_loaded
     *      
     * @param array $config            
     * @return void
     */
    public function __construct($config = array())
    {
        $this->CI = & get_instance();
        $this->CI->lang->load('calendar');
        
        empty($config) or $this->initialize($config);
        
        log_message('info', 'Calendar Class Initialized');
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Initialize the user preferences
     *
     * Accepts an associative array as input, containing display preferences
     *
     * @param
     *            array config preferences
     * @return CI_Calendar
     */
    public function initialize($config = array())
    {
        foreach ($config as $key => $val) {
            if (isset($this->$key)) {
                $this->$key = $val;
            }
        }
        
        // Set the next_prev_url to the controller if required but not defined
        if ($this->show_next_prev === TRUE && empty($this->next_prev_url)) {
            $this->next_prev_url = $this->CI->config->site_url($this->CI->router->class . '/' . $this->CI->router->method);
        }
        
        return $this;
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Generate the calendar
     *
     * @param
     *            int the year
     * @param
     *            int the month
     * @param
     *            array the data to be shown in the calendar cells
     * @return string
     */
    public function generate($year = '', $month = '', $data = array())
    {
        $local_time = time();
        
        // Set and validate the supplied month/year
        if (empty($year)) {
            $year = date('Y', $local_time);
        } elseif (strlen($year) === 1) {
            $year = '200' . $year;
        } elseif (strlen($year) === 2) {
            $year = '20' . $year;
        }
        
        if (empty($month)) {
            $month = date('m', $local_time);
        } elseif (strlen($month) === 1) {
            $month = '0' . $month;
        }
        
        $adjusted_date = $this->adjust_date($month, $year);
        
        $month = $adjusted_date['month'];
        $year = $adjusted_date['year'];
        
        // Determine the total days in the month
        $total_days = $this->get_total_days($month, $year);
        
        // Set the starting day of the week
        $start_days = array(
            'sunday' => 0,
            'monday' => 1,
            'tuesday' => 2,
            'wednesday' => 3,
            'thursday' => 4,
            'friday' => 5,
            'saturday' => 6
        );
        $start_day = isset($start_days[$this->start_day]) ? $start_days[$this->start_day] : 0;
        
        // Set the starting day number
        $local_date = mktime(12, 0, 0, $month, 1, $year);
        $date = getdate($local_date);
        $day = $start_day + 1 - $date['wday'];
        
        while ($day > 1) {
            $day -= 7;
        }
        
        // Set the current month/year/day
        // We use this to determine the "today" date
        $cur_year = date('Y', $local_time);
        $cur_month = date('m', $local_time);
        $cur_day = date('j', $local_time);
        
        $is_current_month = ($cur_year == $year && $cur_month == $month);
        
        // Generate the template data array
        $this->parse_template();
        
        // Begin building the calendar output
        $out = $this->replacements['table_open'] . "\n\n" . $this->replacements['heading_row_start'] . "\n";
        
        // "previous" month link
        if ($this->show_next_prev === TRUE) {
            // Add a trailing slash to the URL if needed
            $this->next_prev_url = preg_replace('/(.+?)\/*$/', '\\1/', $this->next_prev_url);
            
            $adjusted_date = $this->adjust_date($month - 1, $year);
            $out .= str_replace('{previous_url}', $this->next_prev_url . $adjusted_date['year'] . '/' . $adjusted_date['month'], $this->replacements['heading_previous_cell']) . "\n";
        }
        
        // Heading containing the month/year
        $colspan = ($this->show_next_prev === TRUE) ? 5 : 7;
        
        $this->replacements['heading_title_cell'] = str_replace('{colspan}', $colspan, str_replace('{heading}', $this->get_month_name($month) . '&nbsp;' . $year, $this->replacements['heading_title_cell']));
        
        $out .= $this->replacements['heading_title_cell'] . "\n";
        
        // "next" month link
        if ($this->show_next_prev === TRUE) {
            $adjusted_date = $this->adjust_date($month + 1, $year);
            $out .= str_replace('{next_url}', $this->next_prev_url . $adjusted_date['year'] . '/' . $adjusted_date['month'], $this->replacements['heading_next_cell']);
        }
        
        $out .= "\n" . $this->replacements['heading_row_end'] . "\n\n" . 
        // Write the cells containing the days of the week
        $this->replacements['week_row_start'] . "\n";
        
        $day_names = $this->get_day_names();
        
        for ($i = 0; $i < 7; $i ++) {
            $out .= str_replace('{week_day}', $day_names[($start_day + $i) % 7], $this->replacements['week_day_cell']);
        }
        
        $out .= "\n" . $this->replacements['week_row_end'] . "\n";
        
        // Build the main body of the calendar
        while ($day <= $total_days) {
            $out .= "\n" . $this->replacements['cal_row_start'] . "\n";
            
            for ($i = 0; $i < 7; $i ++) {
                if ($day > 0 && $day <= $total_days) {
                    $out .= ($is_current_month === TRUE && $day == $cur_day) ? $this->replacements['cal_cell_start_today'] : $this->replacements['cal_cell_start'];
                    
                    if (isset($data[$day])) {
                        // Cells with content
                        $temp = ($is_current_month === TRUE && $day == $cur_day) ? $this->replacements['cal_cell_content_today'] : $this->replacements['cal_cell_content'];
                        $out .= str_replace(array(
                            '{content}',
                            '{day}'
                        ), array(
                            $data[$day],
                            $day
                        ), $temp);
                    } else {
                        // Cells with no content
                        $temp = ($is_current_month === TRUE && $day == $cur_day) ? $this->replacements['cal_cell_no_content_today'] : $this->replacements['cal_cell_no_content'];
                        $out .= str_replace('{day}', $day, $temp);
                    }
                    
                    $out .= ($is_current_month === TRUE && $day == $cur_day) ? $this->replacements['cal_cell_end_today'] : $this->replacements['cal_cell_end'];
                } elseif ($this->show_other_days === TRUE) {
                    $out .= $this->replacements['cal_cell_start_other'];
                    
                    if ($day <= 0) {
                        // Day of previous month
                        $prev_month = $this->adjust_date($month - 1, $year);
                        $prev_month_days = $this->get_total_days($prev_month['month'], $prev_month['year']);
                        $out .= str_replace('{day}', $prev_month_days + $day, $this->replacements['cal_cell_other']);
                    } else {
                        // Day of next month
                        $out .= str_replace('{day}', $day - $total_days, $this->replacements['cal_cell_other']);
                    }
                    
                    $out .= $this->replacements['cal_cell_end_other'];
                } else {
                    // Blank cells
                    $out .= $this->replacements['cal_cell_start'] . $this->replacements['cal_cell_blank'] . $this->replacements['cal_cell_end'];
                }
                
                $day ++;
            }
            
            $out .= "\n" . $this->replacements['cal_row_end'] . "\n";
        }
        
        return $out .= "\n" . $this->replacements['table_close'];
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Get Month Name
     *
     * Generates a textual month name based on the numeric
     * month provided.
     *
     * @param
     *            int the month
     * @return string
     */
    public function get_month_name($month)
    {
        if ($this->month_type === 'short') {
            $month_names = array(
                '01' => 'cal_jan',
                '02' => 'cal_feb',
                '03' => 'cal_mar',
                '04' => 'cal_apr',
                '05' => 'cal_may',
                '06' => 'cal_jun',
                '07' => 'cal_jul',
                '08' => 'cal_aug',
                '09' => 'cal_sep',
                '10' => 'cal_oct',
                '11' => 'cal_nov',
                '12' => 'cal_dec'
            );
        } else {
            $month_names = array(
                '01' => 'cal_january',
                '02' => 'cal_february',
                '03' => 'cal_march',
                '04' => 'cal_april',
                '05' => 'cal_mayl',
                '06' => 'cal_june',
                '07' => 'cal_july',
                '08' => 'cal_august',
                '09' => 'cal_september',
                '10' => 'cal_october',
                '11' => 'cal_november',
                '12' => 'cal_december'
            );
        }
        
        return ($this->CI->lang->line($month_names[$month]) === FALSE) ? ucfirst(substr($month_names[$month], 4)) : $this->CI->lang->line($month_names[$month]);
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Get Day Names
     *
     * Returns an array of day names (Sunday, Monday, etc.) based
     * on the type. Options: long, short, abr
     *
     * @param
     *            string
     * @return array
     */
    public function get_day_names($day_type = '')
    {
        if ($day_type !== '') {
            $this->day_type = $day_type;
        }
        
        if ($this->day_type === 'long') {
            $day_names = array(
                'sunday',
                'monday',
                'tuesday',
                'wednesday',
                'thursday',
                'friday',
                'saturday'
            );
        } elseif ($this->day_type === 'short') {
            $day_names = array(
                'sun',
                'mon',
                'tue',
                'wed',
                'thu',
                'fri',
                'sat'
            );
        } else {
            $day_names = array(
                'su',
                'mo',
                'tu',
                'we',
                'th',
                'fr',
                'sa'
            );
        }
        
        $days = array();
        for ($i = 0, $c = count($day_names); $i < $c; $i ++) {
            $days[] = ($this->CI->lang->line('cal_' . $day_names[$i]) === FALSE) ? ucfirst($day_names[$i]) : $this->CI->lang->line('cal_' . $day_names[$i]);
        }
        
        return $days;
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Adjust Date
     *
     * This function makes sure that we have a valid month/year.
     * For example, if you submit 13 as the month, the year will
     * increment and the month will become January.
     *
     * @param
     *            int the month
     * @param
     *            int the year
     * @return array
     */
    public function adjust_date($month, $year)
    {
        $date = array();
        
        $date['month'] = $month;
        $date['year'] = $year;
        
        while ($date['month'] > 12) {
            $date['month'] -= 12;
            $date['year'] ++;
        }
        
        while ($date['month'] <= 0) {
            $date['month'] += 12;
            $date['year'] --;
        }
        
        if (strlen($date['month']) === 1) {
            $date['month'] = '0' . $date['month'];
        }
        
        return $date;
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Total days in a given month
     *
     * @param
     *            int the month
     * @param
     *            int the year
     * @return int
     */
    public function get_total_days($month, $year)
    {
        $this->CI->load->helper('date');
        return days_in_month($month, $year);
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Set Default Template Data
     *
     * This is used in the event that the user has not created their own template
     *
     * @return array
     */
    public function default_template()
    {
        return array(
            'table_open' => '<table border="0" cellpadding="4" cellspacing="0">',
            'heading_row_start' => '<tr>',
            'heading_previous_cell' => '<th><a href="{previous_url}">&lt;&lt;</a></th>',
            'heading_title_cell' => '<th colspan="{colspan}">{heading}</th>',
            'heading_next_cell' => '<th><a href="{next_url}">&gt;&gt;</a></th>',
            'heading_row_end' => '</tr>',
            'week_row_start' => '<tr>',
            'week_day_cell' => '<td>{week_day}</td>',
            'week_row_end' => '</tr>',
            'cal_row_start' => '<tr>',
            'cal_cell_start' => '<td>',
            'cal_cell_start_today' => '<td>',
            'cal_cell_start_other' => '<td style="color: #666;">',
            'cal_cell_content' => '<a href="{content}">{day}</a>',
            'cal_cell_content_today' => '<a href="{content}"><strong>{day}</strong></a>',
            'cal_cell_no_content' => '{day}',
            'cal_cell_no_content_today' => '<strong>{day}</strong>',
            'cal_cell_blank' => '&nbsp;',
            'cal_cell_other' => '{day}',
            'cal_cell_end' => '</td>',
            'cal_cell_end_today' => '</td>',
            'cal_cell_end_other' => '</td>',
            'cal_row_end' => '</tr>',
            'table_close' => '</table>'
        );
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Parse Template
     *
     * Harvests the data within the template {pseudo-variables}
     * used to display the calendar
     *
     * @return CI_Calendar
     */
    public function parse_template()
    {
        $this->replacements = $this->default_template();
        
        if (empty($this->template)) {
            return $this;
        }
        
        if (is_string($this->template)) {
            $today = array(
                'cal_cell_start_today',
                'cal_cell_content_today',
                'cal_cell_no_content_today',
                'cal_cell_end_today'
            );
            
            foreach (array(
                'table_open',
                'table_close',
                'heading_row_start',
                'heading_previous_cell',
                'heading_title_cell',
                'heading_next_cell',
                'heading_row_end',
                'week_row_start',
                'week_day_cell',
                'week_row_end',
                'cal_row_start',
                'cal_cell_start',
                'cal_cell_content',
                'cal_cell_no_content',
                'cal_cell_blank',
                'cal_cell_end',
                'cal_row_end',
                'cal_cell_start_today',
                'cal_cell_content_today',
                'cal_cell_no_content_today',
                'cal_cell_end_today',
                'cal_cell_start_other',
                'cal_cell_other',
                'cal_cell_end_other'
            ) as $val) {
                if (preg_match('/\{' . $val . '\}(.*?)\{\/' . $val . '\}/si', $this->template, $match)) {
                    $this->replacements[$val] = $match[1];
                } elseif (in_array($val, $today, TRUE)) {
                    $this->replacements[$val] = $this->replacements[substr($val, 0, - 6)];
                }
            }
        } elseif (is_array($this->template)) {
            $this->replacements = array_merge($this->replacements, $this->template);
        }
        
        return $this;
    }
}
